How does the NuDown jacket work? Well, instead of relying on conventional insulation material, their clothing will sport an airtight layer instead. This unique layer can be inflated up to the desired level via a hand-pump, or through the use of a canister of argon gas (thankfully, you do not need to blow into it), for additional insulation. After all, a thick layer of air works wonders as an insulator against the cold on the outside.
At least you can adjust the amount of insulation that you would require at any point in time, but the potential downsides would be having NuDown jackets that are not only heavier, but also have them burn a bigger hole in your pockets.